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Is it possible to charge a car battery off of a moving car tire? Answered

6 Replies

Yes it is possible, the automotive industry was toying with the idea of having 4 independent DC motors at each wheel that would not only accelerate the vehicle, but it also charged the batteries, and when the brake pedal was applied it would turn the case magnets inside of the motors into an electric brake and the motors armature acted like the brake rotor. I personally don't think it would work since the general rule for batteries seems to be the amount of power used to drive the vehicle is twice the amount you could put back in. After starting your motor it takes roughly 7 miles of driving at highway speed to bring the volts back to it's previous state.

Yes, but it only makes sense if the moving car tire is on another car. Otherwise, you're just trying to what the alternator already does, except considerably less efficiently.

Now, if the generator (or alternator) only operated during braking or hill descents, that is slightly more sensible. But, it's doubtful that the small amount of energy recovered will make up for the cost, complexity, and weight of the generator, unless you're talking electric vehicle, in which case you've already got all the necessary bits (except maybe some extra electronics to make regenerative braking work).

i was wondering this also. seems like a source of much energy you're already paying for- why not harvest it and extend your gas tank? is it possible to hook the battery up so it would charge as the tires move and when you have enough energy just switch fom gas to this extra battery and viola!- free extra energy!

As lemonie suggested, yes, but why, when you already have an alternator in the vehicle that can, in many cases, do the job?
You can charge smaller batteries just by hooking up an appropriate battery or charging module and battery (for batteries with voltage ratings lower than 12V) to the cigarette lighter/accessory outlets in the vehicle, and for larger capacity 12V batteries, (like a second auto battery or similar) either buy or make a charging unit to share the alternator with the automobile's primary battery (hint: look for RV battery charging modules).